1. Berkeley Borehole Networks Cooperative Agreement
Overview of Networks
Scientific Contributions
Needs for Maintaining the Networks

2. Hayward Fault Network (HFN)
25 borehole stations in total
10 Operating free field (NHFN and mPBO ) sites
3 Operating bridge sites
12 non-operating bridge sites (Caltrans funding will allow operation of some)
2 new sites being developed
Sources of Installation Support
USGS NEHRP
NSF
EPRI
Caltrans
UC/LLNL/LBNL
Sources of Operations Support
BSL

3. High Resolution Seismic Network (HRSN)
13 borehole stations in total
Sources of Installation Support
USGS NEHRP
NSF
Sources of Operations Support
BSL

4. Waveform Data: HRSN

5. HRSN: Tremor Observations
Nadeau et al., 2004

6. Waveform Data: NHFN October 19, 2003 Orinda Sequence
4000+ fore- and aftershocks down to M= -2
Courtesy of Peggy Hellweg

7. Orinda Sequence M3.5 Mainshock-3 -2 -1 1 2 3
x 10-4
x 10 -4
14:35:27
14:35:28
14:35:29
14:35:30 Z H1 H2
UTC Time on 19 October 2003
Ground Velocity (m/s)
S-P=0.7 sec
Courtesy of Peggy Hellweg

9. BSL and Collaborative Research Conducted using Data from the Borehole Networks
HRSN Repeater Catalog
NCSN Catalog
Seismic moments, waveforms and event locations are nearly identical, and recurrence times are quasi-periodic
Nadeau and McEvilly, 1997

10. Comparison of slip rate, 2004 coseismic and postseismic slip
Inferred Slip Rate from Nadeau and McEvilly (1999)

11. Korneev et al found 6% velocity variation in the fault zone by modeling reflected and transmitted wavefields from vibroseis source

12. Korneev et al modeled station gathers from 1000s of microearthquakes to image fault zone guided waves and fault zone Q structure

13. Hayward Fault Repeating Earthquakes and Slip Rate
Burgmann et al estimates of Hayward fault creep rate from geodetic and characteristically repeating micro earthquakes suggests the seismic potential of the NHF may be less than previously thought.

14. Other Researchers using Borehole waveform data, data products, and requesting data products
SAFOD related research (Ellsworth, Thurber, Roecker, Hole, Li, Vidale, Hickmann, Malin)
Beroza – temporal changes in Vp, Vs, and non-linearity
Silver – migration of scatterers
Vidale – fault healing, anisotropy, fault zone guided waves
Korneev – fault zone guided waves
Ellsworth – time dependent earthquake forecast models
Beeler – compare natural and laboratory repeating event statistics
Rubin – requesting event catalogs
Abercrombie - waveform and catalog data for scaling research
Johnston - correlating strain and tremor occurrence
Spudich - tremor catalog to examine UPSAR data
* Clear majority of catalog requests are for repeating earthquake and tremor activity since the 2004 Parkfield earthquake

15. Published Research using Borehole Network Project’s Results

16. Published Research Using Borehole Network Project Results

17. Berkeley Borehole Networks Cooperative Agreement
Our Predicament
Historically we have submitted proposals to NEHRP for both borehole network O/M support and Science.
Over the past several years funding has been essentially flat and even cut back moderately while costs, particularly land owner costs have skyrocketed.
The funding shortfall has curtailed our ability to support our science and the involvement and training of our students on these projects.
Should we keep the networks going or let them die and do research?
Additionally, the San Simeon and Parkfield earthquake sequences have greatly increased the numbers of events needing analysis. The present situation is that these events are not being studied.

18. Needs for Maintaining Borehole Networks
Personnel (1 FTE)
field and central site technical issues
data review and quality control
People: Clymer, Nadeau, and Uhrhammer
Est. 100k/year
Equipment, supplies
4k/year (equivalent to complete system electronics renewal of one site per 5 years, or about 1% of replacement cost of HRSN, NHFN (non-bridge), and mPBO sites)
vehicle support 2k/year
Land Owner Costs and Telemetry
HRSN Kester: $4100/year
HRSN Gastro: $6580/year
NHFN $5000/year (five free-field sites)
Annual Total: 122k + 52% (OH)=185k/yr (currently from NEHRP ~ 135k)

19. Needed Data Products
Merged HRSN, HFN, BDSN, and NCSN phase data catalog
In progress at Parkfield (David O.)
Same effort on the Hayward fault?
Automated pattern recognition catalog of highly similar events
Use waveform cross-correlation and pattern recognition to find similar events
Requires some development and computer hardware
Review of high volume HRSN triggers since the San Simeon earthquake
Funding requests to both the USGS and NSF have been declined
Repeating earthquake catalog
Requires review of automated catalog above to distinguish true repeating events

20. Review of high volume HRSN triggers since the San Simeon earthquake
Triggers per hour
Before these earthquake the rate was about 5 triggers per day!
Are these additional triggers events at Parkfield or at San Simeon?

21. Repeating Earthquake Catalog